This application seeks two years funding to support the development of instrumentation to assess the developmental potential of preimplantation embryos and to study the pathophysiology of oocyte dysfunction. The investigators are particularly interested in the study of age related oocyte dysfunction. The program involves a collaboration between the Director of the BioCurrents Research Center (MBL & NCRR), Dr. Peter J.S. Smith; and the Director of the IVF Clinic (Women and Infants) and Reproductive Medicine Laboratory (MBL), Dr. David Keefe. Central to this instrument development is the modification of established non-invasive, self-referencing, ion-selective probes to operate under environmental conditions capable of sustaining the long-term health of mammalian embryos. This will involve significant changes to present experimental platforms with longer term development of software algorithms to permit remote sensing of embryos and probe positions. The developing instrumentation will be simultaneously tested to explore the biological hypothesis that transmembrane calcium flux is an accurate predictor of embryo viability and oocyte dysfunction. The investigators anticipate this approach will be significantly more sensitive than predictors currently in clinical use. The Golden Hamster will be used as a model and data will be correlated with the age of the donor female, subsequent cell division in vitro and, ultimately, implantation success on transfer to a pseudopregnant recipient. The investigators expect the finished instrumentation to provide new insights into the basic physiology of mammalian oocytes and early embryos and to provide the foundation of clinically applicable assays for preimplantation embryo selection.